A187106
Number of nonempty subsets of {1, 2, ..., n} having pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 495, 543, 615, 727, 1455, 1519, 3039, 3231, 3615, 3871, 7743, 7999, 11167, 11903, 14655, 15487, 30975, 31231, 62463, 69887, 76159, 80255, 89855, 91647, 183295, 192639, 208639, 214271, 428543
Offset: 1
a(4) = 11 because there are 11 nonempty subsets of {1,2,3,4} having pairwise coprime elements: {1}, {2}, {3}, {4}, {1,2}, {1,3}, {1,4}, {2,3}, {3,4}, {1,2,3}, {1,3,4}.
-
f(n,k=1)=if(n==1, return(2)); if(gcd(k,n)==1, f(n-1,n*k)) + f(n-1,k)
a(n)=f(n)-1 \\ Charles R Greathouse IV, Aug 24 2016
A187263
Number of nonempty subsets of {1, 2, ..., n} with <=2 pairwise coprime elements.
Original entry on oeis.org
1, 3, 6, 9, 14, 17, 24, 29, 36, 41, 52, 57, 70, 77, 86, 95, 112, 119, 138, 147, 160, 171, 194, 203, 224, 237, 256, 269, 298, 307, 338, 355, 376, 393, 418, 431, 468, 487, 512, 529, 570, 583, 626, 647, 672, 695, 742, 759, 802, 823
Offset: 1
a(4) = 9 because there are 9 nonempty subsets of {1,2,3,4} with <=2 pairwise coprime elements: {1}, {2}, {3}, {4}, {1,2}, {1,3}, {1,4}, {2,3}, {3,4}.
A187264
Number of nonempty subsets of {1, 2, ..., n} with <=3 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 21, 25, 43, 54, 73, 83, 125, 136, 194, 215, 245, 278, 374, 396, 516, 552, 614, 662, 834, 871, 1018, 1087, 1215, 1285, 1555, 1592, 1900, 2023, 2181, 2298, 2506, 2581, 3013, 3160, 3378, 3497, 4027, 4105, 4689, 4875, 5103
Offset: 1
a(4) = 11 because there are 11 nonempty subsets of {1,2,3,4} with <=3 pairwise coprime elements: {1}, {2}, {3}, {4}, {1,2}, {1,3}, {1,4}, {2,3}, {3,4}, {1,2,3}, {1,3,4}.
A187265
Number of nonempty subsets of {1, 2, ..., n} with <= 4 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 53, 68, 97, 109, 193, 208, 345, 382, 437, 506, 785, 827, 1224, 1310, 1472, 1590, 2253, 2346, 2892, 3100, 3568, 3784, 5070, 5163, 6756, 7277, 7928, 8387, 9301, 9560, 12142, 12790, 13815, 14297, 17795, 18083, 22189
Offset: 1
a(5) = 23 because there are 23 nonempty subsets of {1,2,3,4,5} with <=4 pairwise coprime elements: {1}, {2}, {3}, {4}, {5}, {1,2}, {1,3}, {1,4}, {1,5}, {2,3}, {2,5}, {3,4}, {3,5}, {4,5}, {1,2,3}, {1,2,5}, {1,3,4}, {1,3,5}, {1,4,5}, {2,3,5}, {3,4,5}, {1,2,3,5}, {1,3,4,5}.
A187266
Number of nonempty subsets of {1, 2, ..., n} with <=5 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 225, 241, 450, 496, 565, 663, 1170, 1227, 2055, 2196, 2473, 2666, 4257, 4420, 5709, 6122, 7223, 7664, 11449, 11612, 16776, 18255, 19991, 21178, 23718, 24327, 33888, 35767, 38853, 40157, 54455
Offset: 1
A187267
Number of nonempty subsets of {1, 2, ..., n} with <=6 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 489, 537, 609, 719, 1383, 1446, 2674, 2851, 3204, 3443, 6110, 6329, 8484, 9083, 10930, 11587, 19252, 19471, 31084, 34131, 37428, 39637, 44583, 45640, 69968, 73870, 80421, 82985
Offset: 1
A187268
Number of nonempty subsets of {1, 2, ..., n} with <=7 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 495, 543, 615, 727, 1447, 1511, 2958, 3148, 3528, 3782, 7226, 7473, 10268, 10969, 13379, 14163, 25751, 25998, 45470, 50309, 55111, 58286, 65586, 67035, 112676, 118867, 129387, 133295
Offset: 1
A187269
Number of nonempty subsets of {1, 2, ..., n} with <=8 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 495, 543, 615, 727, 1455, 1519, 3031, 3223, 3607, 3863, 7646, 7901, 10987, 11719, 14393, 15219, 29383, 29638, 55637, 61912, 67681, 71466, 80284, 81965, 149001, 156985, 170628
Offset: 1
A187270
Number of nonempty subsets of {1, 2, ..., n} with <=9 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 495, 543, 615, 727, 1455, 1519, 3039, 3231, 3615, 3871, 7735, 7991, 11151, 11887, 14631, 15463, 30683, 30939, 60578, 67646, 73813, 77845, 87284, 89054, 171020, 179960, 195265
Offset: 1
A187271
Number of nonempty subsets of {1, 2, ..., n} with <=10 pairwise coprime elements.
Original entry on oeis.org
1, 3, 7, 11, 23, 27, 55, 71, 103, 115, 231, 247, 495, 543, 615, 727, 1455, 1519, 3039, 3231, 3615, 3871, 7743, 7999, 11167, 11903, 14655, 15487, 30951, 31207, 62147, 69503, 75765, 79855, 89440, 91230, 180285, 189556, 205432
Offset: 1
Showing 1-10 of 10 results.